The Particle Measurement Programme informal group was established to develop a more sensitive particle measurement system than the long-standing particulate matter mass measurement system. This phase concluded with the adoption into UN Regulations 83 (light duty emissions) and 49 (heavy duty emissions) of the particle number (PN) counting method, together with enhancements to the particulate mass (PM) measurement procedure. Initially the PN protocol was applied for diesel engines/vehicles only in R83.06 and [R49.0x] and subsequently has been extended to cover to spark ignition direct injection engined vehicles R83.06 (draft).

The European Union (EU) has requested further investigation of particle number emissions from spark ignition engines relating to particle size (reduction of the d50 cut off specification) and to emissions under rich operation conditions. Further activities to adapt the procedures/measurement equipment and establish appropriate limit values may be necessary based on the results of these investigations.

The PMP group expects to complete its current mission by June 2016. However, the group’s mandate could be extended in order to transpose the developed procedures into emissions-related global technical regulations, including the upcoming GTR on light vehicle emissions (WLTP).

Moreover, concerns over additional sources of particulates, such as tire and brake wear, have been raised and may require measurement procedures as well.